text:
Can I stop crop dusters repeatedly flying over my home?
I have a crop-duster spraying the fields around me often. He flies over my house no matter what field he is spraying every few minutes. I think he uses my house as a pivot point. The old pilot rarely flew over my place.
My livestock goes nuts. It is annoying. He has to fly low and is loud. I called the company  awhile back and they said he was new and he would talk to him. He is back today flying over repeatedly and I called the company and the owner told me he would call me back. No call back and it goes to voice mail now when I call him.
Is there anything I can do? I told the owner that I understood they may have to fly over once in awhile but this is over the top.

related, if not duplicate: https://aviation.stackexchange.com/questions/8391/1467 (question is tagged EASA, but answers include the US)

Also related, good info about reporting so the FAA can investigate.

Possible duplicate of What are the flight rules for crop dusters?

@fooot  The answer to "what are the rules for cropdusters" doesn't answer the question what an individual can DO in the case of rules being violated. That question is clearly related, but not really a duplicate.

Possible duplicate of Are seaplanes allowed to taxi in residential areas?

https://en.wikipedia.org/wiki/Barrage_balloon

"over the top". Good one.

https://en.wikipedia.org/wiki/S-400_missile_system

https://en.wikipedia.org/wiki/Nike_Hercules

In a rural area pilots can fly pretty low, and are permitted to fly even lower while carrying out a lawful activity such as crop-dusting. Even if the pilot flew at 500 feet above your house, which is probably the maximum that he needs to stay away, it would still be loud and disturbing to your livestock.
You should try to work it out with the company and/or the pilot in an amicable way.
Unless your house is located in a congested area, the minimum altitude the pilot must maintain is 500 ft. However, if your house is located in a sparsely populated area, the pilot may be able to fly much lower than that. However, while the pilot is in the process of spraying, or turning around to spray he is allowed to fly lower than that minimum. Otherwise, the pilot may have to do dangerous steep climbs and descents.
For example, lets say the pilot is in violation of minimum altitude regulations by flying over your house at some minimal altitude below 500 ft. Lets assume you get the pilot busted and the pilot receives a warning, citation, or temporary suspension. When he comes back he can just fly over at 500 ft legally all day long, and that will probably be almost as noisy and disturbing to your livestock.
Alternatively, you can lease a small part of your land to AT&T to put a 1000ft tall cellular antenna on your property.
But seriously, as a pilot, if I heard that my flying was causing you so many problems, I would try to avoid it as best as possible, so long as it doesn't affect safety.

Could you lawfully build such a tower yourself? I assume even a 300 ft mast, which is probably doable, would be enough to scare pilots away. Or, easier, fly kites? (Of course a mast could be an even more valuable landmark...)

After some googling it looks as if radio masts are (locally?) regulated, e.g. see https://library.municode.com/tx/rowlett/codes/code_of_ordinances?nodeId=PTIICOOR_CH62TE_ARTIIANMATO. Not sure whether a reason can be conjured up for a 300ft or so mast, and it would need a permit and cost an inspection. Not sure about "non-purpose" edifices ("it's my new hobby"); the mentioned regulation appears to specifically concern radio antennas. There are likely building and safety codes etc., but in a rural area they may be pretty lenient.

@Devil07, what is your basis for suggesting a violation of minimum altitude regulations by flying over [a] house at 200 ft?

I like the tower idea. https://en.wikipedia.org/wiki/Barrage_balloon

I think the kite idea is much more practical. It is cheap, easy to setup, and is not regulated.

@mongo it was just offered as an example; it may or may not be a violation. If pilot needs to fly at 200ft over OP's house to safely conduct his crop dusting or for landing and take-offs, then its likely not a violation. But, if he is just flying over her house as a reference point all day at 200ft, then he might be violating FAR 91.119 (c), which requires aircraft to fly at 500 feet  above the surface in "other than congested areas" or at distance of 500 feet from any person (i.e. the OP), vessel, vehicle (i.e the OP's tractor), or structure (i.e. barn), in a "sparsely populated" area.

Where's the ATT tower comment?

Actually, for the most parts, radio masts are regulated federally by the FCC. As a ham radio operator, you can build a properly licensed station and could have a 1000 ft tower. You would have to clear it with the FAA if you are near an airport, add lights etc as required, and the locals have a say as far as safety goes, but nothing else (again, as long as it is somehow properly licensed by the FCC). So the locals could dictate where it goes on your property so it could not fall on other people's property, but that's about it.

@Devil07, Your wording suggests that 200 ft might be some threshold for violation of unsafe altitude, which for 14 CFR 137 operations, it is not.

@mongo I tried to make it clear that the 200 ft was a hypothetical by starting the clause with the phrase "lets say that...." Also, it says 200 ft instead of 500 ft (the assumption is that 500 ft is the threshold).  14CFR137 only modifies the part 91 minimum altitudes for "congested areas." And even in congested areas the aircraft can only deviate from part 91 minimums as required "for the proper accomplishment of the agricultural aircraft operations." Thank you for the input, I will try to update and revise so it is more clear.

A series of mega wind turbines along the perimeter of OP's property would be more effective and much more profitable. Vestas V164 produces 8MW each and is 722ft tall.

@Davil07, the facts disagree with your statement that 14CFR137 only modified the part 91 minimum altitudes for "congested areas." I refer you to 14CFR137.49, titled Operations over other than congested areas, and states in part, "an aircraft may be operated over other than congested areas below 500 feet above the surface and closer than 500 feet to persons, vessels, vehicles, and structures..."  That is clearly different than the verbiage in 14CFR91.119.

@mongo You are technically correct, which is the best kind of correct! Part 91 allows a pilot to go below those minimums only for landing and takeoffs, but 137.49 includes "during the actual dispensing operation" and approaches, departures and turnarounds reasonably necessary for operation." I'll incorporate into answer.

Your first sentence sounds a bit as if pilots are required to use higher altitudes when performing unlawful activities ... :)

@HagenvonEitzen  I adjusted the sentence for you. I left "lawful" in there because I wanted to make the point that there isn't anything improper with crop dusting.

The FAA has no authority over structures i.e. buildings and towers. They make recommendations and give advice but local government has the ultimate authority. The FAA will often tie funding of airports to their regulatory wishes - but only on airport property.

@Devil07 Other than the poison they are spraying on your food :)

@Cloud: And on you, if they're spraying crops near where you live.

I did some Pawnee flying years ago, and have fielded a bunch of complaints about ag applicators from people.  Here's my experience:

The FSDO will probably not care.  Ag application is a different set of rules, and there is wide latitude on min safe alt.  You can talk to them, but in my experience, they yawn.
New guys aren't always sensitive to the community.
Personal visits, and if you can nicely talking with the pilot almost always works, but certainly talking with the boss works.
In the states I am most familiar with, there are right to farm legislation, and that makes life easier for farmers (and ag applicators).
Contacting the farmer who is working the land, and having him get you in touch with the applicator is also a good strategy, because farmers care more about their neighbors than applicators.

Having said all that, if you are having livestock issues, then you are being harmed, and there is greater risk. Personally, I would write a letter and send it to the farmer, applicator (if you know who) and the FSDO. Ultimately, in my experience, these matters are resolved only by persuading the applicator to do his field differently.
Sorry, no regurgitation of regulations here, because from your description, the regulations are not going to fix things.
Addendum #1
I changed my mind.  I need to cite 14 CFR 137.49, which states that an aircraft may be operated closer than 500 feet to persons, buildings and the ground.  This is essential for effective ag application, and I can say that 50 foot clearances over buildings are quite common.  100 foot clearances over houses are as well.  How low is too low?  Where will you go when the fan quits, and if you can clear the structure or person and make a suitable off airport landing (or at least argue that you could) then you are fine. The rules are different for congested areas, and the FAA changes their interpretation of congested areas as they wish, but in all my years in aviation, I have never heard of a ag applicator being violated for unsafe altitude, when performing ag operations. So to summarize, over an uncongested area, there is no regulatory figure of X number of feet.  It's not 500, it's not 200. Period.
Finally, if you are aggrieved by the operation, then you may have a tort action, not a regulatory action. In all fairness, there have been successful tort actions where disturbance of livestock and race horses have been involved.

"Where will you go when the fan quits" reminds me of the old joke that the prop is there to keep the pilot cool. Just see him sweat when it stops...

Crop dusting is a legitimate reason to be flying low, so the FAA is almost certainly not going to come to your aid. From their point of view what he's doing is legal, as long as he isn't doing something unsafe.
Obviously you should try every recourse to resolve it amicably. But if you need to involve law enforcement it will be your local sheriff that would deal with things like annoyances and such. Since you have cattle I'm assuming you're not inside a city limit, so it's possible there are no noise ordinances that he's violating. You may have little recourse, legally.
It sounds a little screwy to me. The dusters I've watched never spend more than an hour or so even on large fields. There may be something about the topography or transmission wires or something that makes your place a good spot to turn or something. If you think he might be intentionally harassing you since you called his company that would be something local law enforcement would be responsible for. The FAA would almost certainly tell you to call the local police/sheriff.

There are several fields that surround me that he sprays.  He goes back to his base and refills and comes back.   I have 800ft in front of my house and 1,200 behind it plus several hundred acres all around that he could use to turn without buzzing me repeatedly.   I think he just uses my place as  a pivot point.

Preface: I am not an aviation lawyer and the advice I offer here should not be interpreted as the letter of the law. A real lawyer may be necessary in some instances.
The other answers here cover the regulations well, but as for a course of action, if you feel he is breaching a regulation (flying dangerously low for no reason etc.) you can reach out to your local FSDO to report it.

Contact a FSDO for

Low-flying aircraft

However as mentioned they may not be of much help since he is more than likely well within his rights as they pertain to the FAA.
The other option you have is to speak with your local legislators about a noise abatement for the area which you may have some very legitimate grounds for.


text:
What do different runway depictions mean in the Chart Supplement?
I cannot find a digital Chart Supplement (AF/D) glossary.
What is the length requirement to depict a runway as a dashed line vs. solid black?
The depiction for Melbourne, Florida shows one runway with a dashed line and another as solid.
At JFK, all the runways have dashed lines. What do the different depictions mean?

The glossary I'm looking at (page 13 from the current South Central US Chart Supplement) says that that style of dashed line indicates Runway Centerline Lighting.  So runways that have the dashed lines have lights on the runway.
The complete chart supplements are available online from the FAA, and the glossary for each one is easily found about Page 13 for each section.

Look at Melbourne Florida’s two larger runways. One is dashed symbol. Other is black. Look at JFK. All runways dashed. What is a “Metal” surface?  Thank you for helping.

Thanks very much for answering that. I have the AF/D thru Fly Q and Foreflight, but no glossary

@Rosie for metal surface see this question

Everything the FAA thinks you need to know about charts is in FAA Aeronautical Chart User's Guide.

@Gerry: That document does not seem to cover the Chart Supplements (formerly the AF/D or green books).

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text:
Which aircraft are required to have a black box?
When is an aircraft required to have a Cockpit Voice Recorder or a Flight Data Recorder?

Cockpit Voice Recorders
Required for:

large 4-engined turbine-powered planes
large 4-engined pressurized planes
multiengined turbine-powered planes seating 10+ passengers
multiengined turbine-powered rotorcraft seating 20+ passengers
multiengined turbine-powered planes and rotorcraft seating 6+ passengers and requiring two pilots

Relevant regulations: 14 CFR 121.359, 14 CFR 125.227, 14 CFR 135.151

121.359(d) No person may operate a multiengine, turbine-powered airplane having a passenger seat configuration of 10-19 seats unless it is equipped with an approved cockpit voice recorder
125.227(a) No certificate holder may operate a large turbine engine powered airplane or a large pressurized airplane with four reciprocating engines unless an approved cockpit voice recorder is installed in that airplane and is operated continuously from the start of the use of the checklist (before starting engines for the purpose of flight) to completion of the final checklist at the termination of the flight.
135.151(a) No person may operate a multiengine, turbine-powered airplane or rotorcraft having a passenger seating configuration of six or more and for which two pilots are required by certification or operating rules unless it is equipped with an approved cockpit voice recorder
135.151(b) No person may operate a multiengine, turbine-powered airplane or rotorcraft having a passenger seating configuration of 20 or more seats unless it is equipped with an approved cockpit voice recorder

Flight Data Recorders
Required for:

Multiengine turbine-powered airplanes or rotorcraft seating 10+ passengers
Multiengine turbine-powered airplanes or rotorcraft seating 6+ passengers and requiring two pilots
Large airplanes meant for use either over 25,000 feet
Large turbine-powered airplanes
Turbine-powered transport category planes

Relevant regulations: 14 CFR 91.609, 14 CFR 121.343, 14 CFR 121.344,
14 CFR 135.152

91.609(c)(1) No person may operate a U.S. civil registered, multiengine, turbine-powered airplane or rotorcraft having a passenger seating configuration, excluding any pilot seats of 10 or more that has been manufactured after October 11, 1991, unless it is equipped with one or more approved flight recorders that utilize a digital method of recording and storing data and a method of readily retrieving that data from the storage medium, that are capable of recording the data specified in appendix E to this part, for an airplane, or appendix F to this part, for a rotorcraft, of this part within the range, accuracy, and recording interval specified, and that are capable of retaining no less than 8 hours of aircraft operation.
91.609(e) Unless otherwise authorized by the Administrator, after October 11, 1991, no person may operate a U.S. civil registered multiengine, turbine-powered airplane or rotorcraft having a passenger seating configuration of six passengers or more and for which two pilots are required by type certification or operating rule unless it is equipped with an approved cockpit voice recorder that: (1) Is installed in compliance with § 23.1457(a)(1) and (2), (b), (c), (d)(1)(i), (2) and (3), (e), (f), and (g); § 25.1457(a)(1) and (2), (b), (c), (d)(1)(i), (2) and (3), (e), (f), and (g); § 27.1457(a)(1) and (2), (b), (c), (d)(1)(i), (2) and (3), (e), (f), and (g); or § 29.1457(a)(1) and (2), (b), (c), (d)(1)(i), (2) and (3), (e), (f), and (g) of this chapter, as applicable; and (2) Is operated continuously from the use of the checklist before the flight to completion of the final checklist at the end of the flight.
121.343(b) No person may operate a large airplane type certificated up to and including September 30, 1969, for operations above 25,000 feet altitude, or a turbine-engine powered airplane certificated before the same date, unless it is equipped before May 26, 1989 with one or more approved flight recorders that utilize a digital method of recording and storing data and a method of readily retrieving that data from the storage medium.
121.344(a) Except as provided in paragraph (l) of this section, no person may operate under this part a turbine-engine-powered transport category airplane unless it is equipped with one or more approved flight recorders that use a digital method of recording and storing data and a method of readily retrieving that data from the storage medium.

Exceptions: For aircraft manufactured before August 18, 1997, the following aircraft types need not comply with this section: Bell 212, Bell 214ST, Bell 412, Bell 412SP, Boeing Chinook (BV-234), Boeing/Kawasaki Vertol 107 (BV/KV-107-II), deHavilland DHC-6, Eurocopter Puma 330J, Sikorsky 58, Sikorsky 61N, Sikorsky 76A. [src: 14 CFR 135.152(k)]
Additionally, the NBAA has links to summaries, but I do not have an account with them and was unable to retrieve the data.

I changed them to bullets so it was a little clearer

Do you know if this is based on ICAO recommendations by any chance?

I didn't look up ICAO guidelines because he tagged it faa-regulations but I can later if desired

91.609(e) requires a CFR under Part 91 (under some conditions).  The issue that I have with the way that it is written now is that each bullet only applies under some circumstances.  For instance, if you are flying a 4 engine pressurized airplane under Part 135, the CVR isn't required unless it also falls into one of the 135 regs that you quoted (since 121 and 135 never apply at the same time).  The way that the summary is written makes it sound like all 4 engine pressurized airplanes must have a CVR at all times though.

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text:
Is there any difference between the Boeing 787 and the 737 MAX?
I've just done some research on the Boeing 787 and the 737. But the 787 and 737 MAX seem almost completely alike. Are there any differences between the 787 and the 737 MAX?

Can't help but wondering what "research" you may have done to come to the conclusion that two completely different aircraft are "almost completely alike"!

The 787 was a brand new design. The biggest new feature is the extensive use of composite materials throughout the aircraft. The new design also uses electrical systems instead of hydraulic and bleed air systems that are used on most other aircraft. It is a wide-body aircraft, intended to carry large numbers of passengers over long ranges. The new design mostly replaces the older 767 model.
The 737 MAX is mostly a re-engine of a very old design. Though much has changed in multiple generations since the original 737 design, it still retains many differences from the 787. The 737 still has the same fuselage cross-section, and the aircraft is still primarily built from aluminum. Aside from fly-by-wire spoilers, hydraulics and bleed air are still used as before. While the new engines on the MAX do have chevrons like those on the 787, they are from a different manufacturer. The other key feature of the MAX, the AT winglets, distinguish it from the 787, with uses much more simple raked tips. The 737 still carries a much lower number of passengers, and is intended for shorter routes.

The main difference is size and purpose. Despite being larger than most 737 variants, the 737-MAX is still a smaller, short haul plane. It carries 180 passengers to the 787's 280, has a range of 3630 nautical miles to the 787s 7635. Above all, the 737-MAX is still a narrow bodied jet, while the 787 is a wide body. All of this means that the 737 MAX is still a smaller jet better tailored to domestic flights, while the 787 is a medium to large jet (depending on the variant) intended for international flying.

But, other than all that, they're almost completely alike.  Because, you know, Research.


text:
What is the procedure for getting permission to operate an aircraft within a pop-up VIP TFR?
Consider a situation where there is a Temporary Flight Restriction (TFR) due to VIP movement (i.e. the President of the United States is in Los Angeles), and I am based at an airport that is within the TFR.  I'm a VFR pilot and I want to go for a little flight from my airfield that doesn't have a control tower, exit the TFR, and then return later in the afternoon (re-entering the TFR) and land at the same airport.
What would be the procedure to get permission to:

Take off and exit the TFR-covered area (non-towered airport), and
Return to the same field later on a different flight (same
non-towered airfield)?

All the VIP TFRs I've seen have been very clear on the requirements, typically stating something like "Must be on a filed flight plan, under ATC direction".   I'd say, just read the TFR closely, and follow those instructions to the letter.

Also make sure you call FSS and discuss the TFR as it pertains to your flight.

"temporary TFR" = temporary temporary flight restriction

Usually when the President visits LA or San Francisco there are one or more inner rings and at least one outer ring. The inner rings are usually 10 nm in diameter and you can’t enter them under any conditions. The outer rings, on the other hand, are able to be flown into if you are on a VFR or IFR flight plan and in continuous contact with ATC. Here’s a portion of the TFR at Martha’s Vinyard.

FOR OPERATIONS WITHIN THE AIRSPACE BETWEEN THE 10 NMR AND 30 NMR
  AREA(S) LISTED ABOVE, KNOWN AS THE OUTER RING(S): ALL AIRCRAFT
  OPERATING WITHIN THE OUTER RING(S) LISTED ABOVE ARE LIMITED TO
  AIRCRAFT ARRIVING OR DEPARTING LOCAL AIRFIELDS, AND WORKLOAD
  PERMITTING, ATC MAY AUTHORIZE TRANSIT OPERATIONS. AIRCRAFT MAY NOT
  LOITER. ALL AIRCRAFT MUST BE ON AN ACTIVE IFR OR VFR FLIGHT PLAN WITH
  A DISCRETE CODE ASSIGNED BY AN AIR TRAFFIC CONTROL (ATC) FACILITY.
  AIRCRAFT MUST BE SQUAWKING THE DISCRETE CODE PRIOR TO DEPARTURE AND AT
  ALL TIMES WHILE IN THE TFR AND MUST REMAIN IN TWO-WAY RADIO
  COMMUNICATIONS WITH ATC.

If you are departing or landing at an non-towered field, you need two radios (or an Garmin SL30 radio) to monitor ATC and communicate on the CTAF.
I have done it lots of times VFR into LA and it really isn’t much different than getting flight following.
I don’t have any experience with departing from a non-towered airport into the TFR, since the last time I entered the TFR the approach end of the runway at Catalina Island was in the 30 mile ring, but the departure end was not. So I don’t know for sure but from talking to the people at the FBO and reading the TFR, I think you need to open you flight plan either by phone or on the radio (Hawthorne radio would be who you call and the frequency depends on where you are in the LA basin), contact ATC (in this case LA Center, again frequency varies) on the ground before you take off, then make your normal calls on the CTAF. Then contact ATC again when you are airborne.

It depends on the TFR, sometimes simply communicating with the ATC that controls that area will be sufficient, other times you might need to have a flight plan and a clearance, other times you simply might not be able to do it.
The NOTAM for the specific TFR that you wish to fly through should have the information you need.  You can also call Flight Service and they can help you accomplish what needs to be done.


text:
Can a pilot over the age of 65 exercise the privileges of a commercial pilot license under FAA Part 91 in the Bahamas?
I am hearing there may be a problem with flying in the Bahamas over the age of 65 as a commercial pilot, even under 14 CFR 91. Because the pilots are being compensated they may consider this a commercial operation which then would be age limited to 65 as per ICAO regulations. Is there gray area here or is there no problem flying under 14 CFR 91 over the age of 65 in the Bahamas?

There should not be a problem as long as you are flying under Part 91 because the age restriction which you refer to does not apply to all commercial pilot operations.
14 CFR 61.3 is consistent with the ICAO rule which you refer to and covers a US pilot, flying a US registered aircraft internationally and states:

(j) Age limitation for certain operations
(1) Age limitation. No person who holds a pilot certificate issued
  under this part may serve as a pilot on a civil airplane of U.S.
  registry in the following operations if the person has reached his or
  her 60th birthday or, in the case of operations with more than one
  pilot, his or her 65th birthday:
(i) Scheduled international air services carrying passengers in
  turbojet-powered airplanes;
(ii) Scheduled international air services carrying passengers in
  airplanes having a passenger-seat configuration of more than nine
  passenger seats, excluding each crewmember seat;
(iii) Nonscheduled international air transportation for compensation
  or hire in airplanes having a passenger-seat configuration of more
  than 30 passenger seats, excluding each crewmember seat; or
(iv) Scheduled international air services, or nonscheduled
  international air transportation for compensation or hire, in
  airplanes having a payload capacity of more than 7,500 pounds.
(2) Definitions.
(i) "International air service," as used in this paragraph (j), means
  scheduled air service performed in airplanes for the public transport
  of passengers, mail, or cargo, in which the service passes through the
  airspace over the territory of more than one country.
(ii) "International air transportation," as used in this paragraph
  (j), means air transportation performed in airplanes for the public
  transport of passengers, mail, or cargo, in which the service passes
  through the airspace over the territory of more than one country.

Each of the bolded sections (added by me) show how each part is ruled out for a Part 91 operation as you describe.
Along the same lines, the ICAO SARP that you are referring to governs "commercial air transport operations," and not all commercial operations.  Part 91 flights do not fall under the annex with these requirements.
That being said, it is a foreign country and they can make their own laws which do not necessarily have to agree with any of this.  To be sure, you can always contact the FBO that you intend to use and ask them, or obtain a copy of the Bahamas AIP (I wasn't able to find a free copy) and see what it says.
Being based in South Florida and doing lots of flying to the Bahamas, I haven't heard of a problem with this (although I haven't specifically been looking for it either).


text:
How does a rotary piston (radial) engine work?
How does a Gnome rotary piston engine work?  I would like to see how it works in detail, possibly with text explanation.

http://www.animatedengines.com/gnome.html

Yes..thank you..I mean like Gnome engine

Wikipedia has a couple of animations. Are they "good"? If not, what's wrong with them?

For the people voting this as off-topic, what about this question?

Asking how something works can be on-topic.  Asking for an external resource is usually off-topic on most (all?) SE sites.

http://enginehistory.org/Piston/Before1925/Rotaries/GnomeMonosoupape.pdf

Link from @Gerry 's comment: http://www.animatedengines.com/gnome.html
Short version: take a radial and attach the output shaft to the aircraft firewall/structure.  Feed the intake through the shaft, let the exhaust go where it goes.  Fasten the propeller to the crankcase.
These engines were usually lubricated by mixing oil in the fuel, and passing the intake charge through the crankcase (similar to a modern 2-stroke engine, though without the pressurized crankcase).  Spark was produced by a fixed magneto and distributed to the plugs by a gap contact similar to that in an old style auto distributor.
Many of these engines had no effective throttle, or could only throttle a little (35%, maybe even 50% minimum power).  If you see an air show with an original or repro aircraft using the correct engine, you'll hear them blipping the ignition off and back on during landing approach, as that's the only way to reduce power sufficiently to land.

The oil for lubrication was usually castor oil, which explains the elaborate scarfs worn by many pilots. Failing to put those over your mouth during flight meant that you would spend hours on the loo after landing.

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text:
Calculating distance from VOR station with radial and heading
I am currently struggling to understand the following question regarding a VOR station and an aircraft. The aircraft is found in the 30 degree radial from the VOR station at time T(1) and T(2). During the 10 minutes between T(1) and T(2) the aircraft maintains a heading of 120 degrees from magnetic north at 120 knots ground speed. The question goes like so:

At time t(1) an airborne VOR receiver shows that the aircraft is on the 30deg radial from a VOR station. The pilot maintains a ground track heading of 120deg with respect to magnetic North and 120 knots ground speed. At time t(2) , 10 minutes later than t(1) , the VOR receiver indicates that the aircraft is on the 30deg radial from the same station.
  Assuming no errors, what is the pilot’s distance from the VOR station at time t(2) ? If the pilot had access to airspeed, can the range be determined from the VOR measurements? Can it be determined if the pilot had access to ground speed and ground track heading?

I'm not quite positive of my understanding of the situation. To my understanding the heading indicates the direction the aircraft is pointing in is 120 degrees with respect to magnetic North however its course must be either be 30 degrees with respect to magnetic North or 210 degrees with respect to magnetic North, allowing it to stay in the station's 30 degree radial. Would my understanding of the situation be correct?

Bad news: the question is unanswerable.
Good news: you're right to be confused!

With a groundspeed of 120 knots and a constant ground track, after 10 minutes the airplane will have moved 20 miles in a straight line. There's no getting around this fact.

If the airplane doesn't parallel a radial, and yet it moves, the radial it's on must change.

If it's still indicating the same radial after non-parallel movement, the only option is that the indicator is in error.  But the question removes that possibility.

The only way I can think to make this situation possible is that maybe you've tuned the world's most bizarre VOT. But even still there's no possibility for a valid answer for the question.

The original question:

At time t(1) an airborne VOR receiver shows that the aircraft is on the 30deg radial from a VOR station. The pilot maintains a ground track heading of 120deg with respect to magnetic North and 120 knots ground speed. At time t(2) , 10 minutes later than t(1) , the VOR receiver indicates that the aircraft is on the 30deg radial from the same station. Assuming no errors, what is the pilot’s distance from the VOR station at time t(2) ? If the pilot had access to airspeed, can the range be determined from the VOR measurements? Can it be determined if the pilot had access to ground speed and ground track heading?

Agreed, that's probably what was meant. Minutes*60/degrees=ETA to the station, but the question is flawed

"Flawed" is a real polite term for that question.  It's a mess!

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text:
Can I retake my instrument rating written and practical exam with the FAA?
I was looking to get my restricted ATP at a university, but one of the requirements is to get my instrument rating from that university.  Since I already have my instrument rating, but have not flown for 20 years, I would like to get my rating again through the university. Is it possible to retake my instrument rating again with the FAA?  This would allow me to get my Restricted ATP with only 1,000 hours with 60 aviation credit hours from the university vs 1500 hours.

While I’m not familiar with the university or if this is really their requirement, you could always surrender your pilot certificate... I don’t think you can surrender just the instrument rating. That would mean you would need to do your private checkride and written again. The thought of surrendering any of my hard earned certificates makes me cringe!

I would check more thoroughly if this is what they really require or if there is some other way to validate your IR through them, such as an IPC, or merely graduating from their IR program, even though you have already your rating.

This seems like a University specific policy question.

You don't still have an instrument rating if you've not flown in 20yrs. It is long expired and basically doesn't exist. Its best to do a refresher with CFII and take IPC eval when ready. Or you could redo the whole IR, and or re take the written. I belive the most current written is the one prominent in your file so yeah, go for a better score.

Currency expires, the rating does not.

Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center.


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Is the KC-135 landing gear life limited?
I'm looking for information about the KC-135 landing gear. Specifically I want to know if its life limited and if so where is it documented? If its NOT life limited where is that documented? I'm talking about gear that has regularly been maintained or gear that's been overhauled. I've been looking on the internet and a variety of 135 manuals.

Welcome to aviation stack exchange! Very good question. Gotta upvote.

All landing gears have a limited lifespan unless they undertake in really, really big maintenance, as we saw with the Antonov 225, which went under maintenance for 18 months! And the KC-135 is no exception. Most landing gears last about 20 years, and the one's of the KC-135's is designed for 30 years. But even though it was designed for only 30 years, the operators of the KC-135 still extend it's life by a lot, with as you said, regular maintenance. So, you might see some KC-135 landing gears that are 40 years old!

Aging landing gear life extension
The committee is concerned that the Air Force has been extending the use of aircraft landing gear far beyond their original design life. The KC-135 was designed for a 30-year lifetime, but will retire at 86 years and the B-52, designed for a 30-year life, will retire at 94 years.

Source: congress.gov


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How long can I use an FAA license in Colombia without having to validate it?
What is the maximum range of time that an FAA certificated pilot can stay and fly in Colombia, without the need to validate his license there?

What do you mean by validate?

A pilot's license typically entitels you to fly aircraft registered in your home country, no matter where you fly them. If you want to pilot a foreign-registered aircraft, they need to recognize your license first.

Every country has their own rules and requirements. You’re going to need to be a bit more specific if you’re interested in a certain country.

FAA licence in Colombia!

You could fly US-registered aircraft in Colombia with your FAA license, but if you want to fly Colombian aircraft then you need to either validate your FAA license or get a Colombian one.
You validate your FAA license (or any ICAO license) by getting a Colombian "provisional" license. It remains valid as long as your FAA certificate and medical are valid. See section 2.1.7 of the Colombian regulations:

2.1.7. CONVALIDACIÓN
Cuando la UAEAC convalide una licencia extranjera otorgada por un
  Estado contratante de la OACI, en vez de otorgar su propia licencia,
  hará constar la convalidación mediante autorización apropiada que
  constará en una licencia provisional la cual deberá acompañar a la
  licencia extranjera y reconocerá ésta como equivalente a las otorgadas
  por dicha autoridad aeronáutica colombiana. La validez de la
  autorización no podrá exceder el plazo de validez  de la licencia
  extranjera.

Note that the process of validation depends on your personal situation, especially whether or not you plan to become a Colombian resident (see 2.1.7.1).

Did you just know that or are you a research monster? :-)

@Pugz That's research :-)

it’s beautiful. :-)

24 Calendar months, as you will need a Biennial Flight Review although you could potentially do this abroad if you could find an FAA instructor abroad.
If you have a question I would reach out to the FAA staffer stationed in Columbia

Colombia
Veronica Carpio   (202) 267-0965
  Carl N. Johnson   507-317-5046


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What is the usage ratio of the An-225 Mriya?
Does anyone have data on how much time the An-225 (only one was produced; it is currently the largest aircraft in the world) spends flying/on missions and how much it waits for customers?
This is a very unique aircraft within the scope of contemporary aviation:

Also, there is a copy of the plane - partially built.  Does that suggest there might be need for the completion of second aircraft, to meet demand?

As a privately-operated aircraft, this is probably not going to be a question which is completely answerable. All that is available is best guesses and incomplete information!
That said, the An-225's last tracked flight on FlightAware – as of today – was March 15, 2012 between Bangor, Maine (KBGR) and Port Harcourt, Nigeria (DNPO). That suggests that the An-225 is either being excluded from flight tracks, or simply hasn't visited the US since early 2012.
Aside from that, the only other likely place for flight information is photo sharing websites like airliners.net and flickr, or on youtube. Browsing through flickr, I tried to track down dates of recent photos in unique locations (which is a guess at best):
May 21 2013
June 24 2013
September 25 2013
September 26 2013
November 12 2013
November 17 2013
December 10 2013

I'm sure there are more, but I stopped searching. It looks like it's probably doing charter cargo trips at most a couple of times a month, which is honestly more frequently than I expected! If you're interested, I'd encourage you to track down more on the sources I mentioned.

It visits Leipzig "frequently" Last visit 15.12.2015 http://www.lvz.de/Region/Schkeuditz/Riesenflieger-Antonov-An-225-wieder-in-Leipzig-gelandet

Been in Leipzig often since


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Where exactly is the 700 and 1200 foot AGL for class E airspace measured from?
Are the AGL numbers measured from the Maximum Elevation Figure listed on the sectional?

Front the ground, hence AGL

So where is it measured from
Well, quite literally the 700 foot and 1200 foot numbers are AGL as in the distance between your aircraft and the ground at any point. If there is a mountain in the transition area, the 700-foot AGL figure would have a mountain-shaped "bump" in it. It does not take the AGL figure from some highest figure in the area.

The number you refer to, the Maximum Elevation Figure, is calculated based on the highest obstacle in the quadrangle, see the FAA Website chart legend:

So as you can see, the blue number in the quadrangle does not show the MSL of the "sector" (quadrangle), but it is a simple calculation based on the height of the highest obstacle in the quadrangle + 100 feet and some rounding.
The FAA does a similar calculation for natural terrain features:

The big take-away here, in reference to your answer on another question, is that you cannot use this number to determine if you are within Class-G airspace since it takes an elevation figure from some obstacle (man-made or natural) that may not be anywhere near you. So flying at the MEF + 1200 feet does not mean you are in Class-G since, as in the second example, that mountain is a long way away from Ute Park or Red river (at Red River you would be more like 6200 feet AGL).
The AGL of the highest man-made obstacles are shown on the chart underneath the MSL elevation:

But it may be omitted in congested areas of the map and only shown as MSL.

Since elevations at all points are not listed on a chart how do you know where the class E begins? ATC can't expect you to be carrying a topo map

You know where it begins because the map tells you where (either a transition area or within the "fuzzy blue" borders. The hard part is judging your AGL (as you say). VFR flight does not require prior communications for flying in class-E, so you can theoretically bust in and bust out as much as you want without getting somebody mad (although I wouldn't try that in a transition area).

@TomMcW The VFR sectional shows elevation, it is a topo map

@SteveKuo It shows elevations of obstacles, but not the ground itself

@TomMcW look at the contour lines, e.g. https://skyvector.com/?ll=47.55811385189208,-123.12050061804784&chart=1&zoom=1

@SteveKuo It's the tiny grey numbers? Never noticed those before. It seems staying in class G in a mountainous area would be impossible. It would be akin to terrain-following.

Yes, the tiny gray numbers.
There's no reason to avoid class E. The only reason one might want to stay in class G is for is cloud clearance (clear of clouds vs 500 below + 2000 horizontal) and visibility.

@RonBayer VFR pilots do have to stay out of the E surface area when ceiling and visibility are below 500 and a mile. That's when you need a special VFR clearance. That's when the E airspace really matters.

@JWalters Of course, I wrote that assuming that you were "busting in and out" while following airspace rules. If you bust in and you are lower than VFR requirements, then you are in violation.


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Where and when would a 737-700 be taking off at an altitude of 19 kft?
Another question triggered by reading the 737 technical site; according to this section of the page on the 737's pressurisation system, the 737-700 comes with an option that allows it to safely take off and land at altitudes of up to 19 kilofeet AMSL (my emphasis):

High Altitude Airport Operations System
Is a customer option for operations into airfield elevations of up to 10,000ft (all NG), or 13,500/14,500ft (-6/700 series only). Changes include: Addition of high altitude landing selector switch to transfer to the high altitude mode, cabin altitude at warning horn activation is increased, an extra hour of emergency oxygen (bottles stored in aft cargo compartment), 10 minute take off thrust if engine inop; winglets, carbon brakes and fwd Cof G options are recommended. For the 737-700 the takeoff envelope is increased to 19,000 ft & 0.50Mn. The option is usually taken with increased MLW, carbon brakes and RNP

Yet even the highest-altitude airport in the world - Daocheng Yading (DCY/ZUDC) in western China - is only 14,472 feet AMSL.
What justified providing the 737-700 with the ability to operate from a completely hypothetical airport over 4,500 feet higher than any existing in the world?

Think "density altitude" not MSL.

Ask Nick Fury...

As Ron points out in the comments the question is not so much where as it is when. Aircrafts see the density altitude of the air around it not the true altitude they are at. On a very hot day at a very high altitude airport the density altitude may very well be higher than the true altitude by a significant amount which affects takeoff performance. The FAA provides a nice overview of density altitude here. SO even though there are no airports at 19,000 MSL a lower altitude airport that routinely sees very high temperatures can yield the same situation.

How hot would it have to be at ZUDC (14,472ft AMSL) to have a density altitude of 19,000ft?

@Bianfable  Have to make some assumptions of station pressure, but using the calculator at weather.gov it's possible to estimate.  Using a station pressure of 440 mmHg, a temp of 80 deg F, and a dewpoint of 55 deg F, it computes a Density altitude of 19,007.6 feet.  that is a really hot day for that altitude.


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What makes the left engine on a conventional twin-engine aircraft the critical one?
I already know that this is because of P-factor. But I don't know how to draw a picture or explain this simply?

Wikipedia on P-factor has sufficient picture to give a clue why. And it depends on the direction of propellers rotation: it may be left, right or even none (for counter-rotating props, like on PA-44 or P-38).


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What should be the relative positions of a wing's aerodynamic center and center of gravity?
A positively cambered wing with finite length L has its aerodynamic center AC located 25% from the wing's leading edge. What about the CG of the wing itself (not the CG of the whole plane)? Is there any recommendation for the wing's CG position along the chord?
What about the position of the AC along the wing's span axis? Should the AC be ideally located halfway at L/2 on the wing? What about the position of the wing's CG relative to AC? Should the CG also be at L/2? Why?

1) It doesn't matter much. AC is relevant mostly for aircraft stability, so it is its relationship to the CG of the whole aircraft that matters. Only when the wing is the aircraft (flying wing), the distinction disappears.
Mass distribution (and thus CG) of the wing matters for aeroelastic effects, but then AC is not very relevant.
2) There is little sense in trying to determine spanwise location of AC. AC is related to the lift changes over angle of attack (AoA). When AoA changes, lift (CP) moves forwards and backwards but not sideways. Theoretically, if you consider a half-wing, you might be able to determine spanwise lift movement, esp. on a swept wing. But again, for stability analysis (where AC is relevant), you never need to do that, so you consider the whole wing and relate everything to its mean aerodynamic chord (MAC). L/2, by the way, happens to be on the airplane's plane of symmetry (L is normally the whole wingspan).


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Where should the support points be for testing a model wing in a wind tunnel?
When testing a certain wing profile inside a wind tunnel where should the model, small scale wing be supported? Should the support be under the center of mass of the wing or under the aerodynamic center? If so, why?
My understanding is that, for similarity reasons, the Reynolds and Mach numbers for the model wing tested inside the wind tunnel must be the same as the those for the actual aircraft...

Indeed, the Reynolds and Mach numbers should be the same, or at least similar to the actual aircraft, depending on what you want to measure. For instance, the maximum lift coefficient is very sensitive w.r.t. Re and if you add a Mach number above 0.3, compressibility needs to be taken into account as well (even though quite good correction models exist for this). On the other hand, if you want to measure for instance only the zero-lift angle of attack, the Re doesn't matter much.
Anyway, where you support the airfoil doesn't change the Reynolds or mach numbers. In fact, you can theoretically support it at any point. The lift and drag will always be the same for every point; what changes is the moment that you measure. It might be convenient to choose the aerodynamic center which typically lies at around 25% of the chord, since there the pitching moment doesn't change with angle of attack. But be aware that this location can still very slightly move with AOA in practice. For more information: https://en.wikipedia.org/wiki/Aerodynamic_center.

Thank you. In that case the aerodynamic center becomes the fixed pivotal point.A scale connected to the support point would indicate the lift force produced by the wing (corresponding to the decrease in the force measured by scale). Manometer tubes (making holes on both the top and bottom surfaces of the wing) would measure the local pressures on the top and bottom wing surfaces. Can we still measure the aerodynamic moment about AC if we keep the AoA fixed? The wing would not be allowed to rotate if the wing is at a fixed AoA,correct?

Yes, you can still measure it. The moment about the AC is constant, but non-zero. Or you can compute it from the pressure distribution.
Btw, please don't forget to accept answers on your questions once you're satisfied with the answer and the comments!


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What is the highest and lowest air pressure induced by an aircraft at supersonic speeds?
When an aircraft is supersonic, is the greatest pressure at the wing leading edge, below the wing surface or in front of the shock wave, or another location all together.
Also is the lowest pressure at the upper wing surface or behind the shock wave or another location all together?
Is there a pressure range for these values just to give a point of reference?

When an airplane goes supersonic, it creates a shock wave in front of it. The shock wave compresses the air and slows it down so the speed component orthogonal to the shock front becomes subsonic. See it this way: The airplane sort of creates it's own cocoon of denser and less voluminous air to fly in.
As in subsonic flow, the highest pressure is found behind the tip of the shock wave, in a stagnation point, a point where the speed is reduced to zero, like on the leading edge. The lowest pressure and density is usually found before the shock wave, this is the normal atmospheric pressure. Differently to subsonic flow, in supersonic flow every change in flow speed comes with a large change in density.
There are 2 types of shock waves:

the normal shock wave:
They have nice tables where you can see the speed, pressure and density behind the wave. This shock wave mostly occurs in pipes, like a pitot intake.
Oblique shock waves:
These shock waves are called strong when the mach number after the wave is below 1, and weak when the speed after the wave is still supersonic.

NASA has some nice programs to show how different types of shock waves are formed and how they interact, you can find them here.
The highest pressure is found at the stagnation point of a part which directly faces the oncoming flow. This is the stagnation pressure and it rises with the square of the flow's Mach number. Since a supersonic wing is usually swept, its leading edge will not reach the full stagnation pressure because the flow's speed component orthogonal to the leading edge is not changed.
The lowest pressure is normally found on the upper side of the fuselage. Air is so rarefied there that the vertical tail surface becomes increasingly ineffective at higher Mach numbers. The inclination of the local surface away from the direction of movement can be used with the Prandtl-Meyer expansion calculation to give you a rough idea how low this pressure can drop.

After a compression shock, subsonic speed is only reached normal to the shock front, so speed past an oblique shock is normally still supersonic. Only the component of flow perpendicular to the shock front will become subsonic.

That is correct. Not sure how I can correct my answer to correct that, my knowledge has faded a few bits.

Should I give it a try?

@PeterKämpf: You are very welcome to edit as you please.

Hope you like it. You can always roll back the change if you prefer the old version.

As an addition to the range of pressures (Approximations for aircraft design):
For the static pressure range the lowest pressure can be calculated with c_p,min = 0.8 * c_p,vac where the vacuum pressure is calculated by c_p,vac = -2/(kMa^2) with k the Heat capacity ratio and Ma the Mach number of the outer flow. cp = (2alpha) / sqrt(Ma^2-1). Both are approximations, but can give a first approximation.
further reading:
There is a good book tackling hypersonic aerodynamics. It is by E.H. Hirschel "Selected Aerothermodynamic Design Problems of Hypersonic Flight Vehicles".

@Artur I chanced upon this answer a while ago while searching for references and found it could be improved. Only now I realised that it did not really answer the question (I never looked at the question before - shame on me!).


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How could I calculate the correct distance from the runway to be able to fly a continuous downwind to final turn?
I’m not even sure if this is a safe/allowed procedure at controlled airports so it is purely hypothetical.
Assuming there are calm winds at the field, is there a way to calculate the distance your plane must be from the centerline (see “x”) of the runway while on downwind, so that once you start your turn to base and final thereafter, in a constant rate turn (assume 3 deg./sec.), that you will end up rolling out on the centerline of the runway?
Speed changes (slows) by 27 knots from the beginning of the turn to the end of the turn.
Essentially, if I wanted to execute an 180 degree turn at 3 deg. per second, while slowing the airplane from traffic pattern speed (90 kts) to final approach speed (63 kts), how far away would I need to be from the runway while on downwind before beginning the maneuver? The goal is to be able to use this on any plane given their own specific traffic pattern speed and final approach to landing speed.

This really isn't a standard pattern, why would you do that? You don't want to be turning and making configuration changes while turning, it's one of a few reasons you don't make a semicircular approach.

Although it is not common in the civilian world, I believe procedures like this are quite common in the military. Specifically the Navy.

FWIW, there was a study planned on this, although I never heard about the results. As per another comment, this is common in the military world, including civilian pilots who fly ex-military aircraft.

Turning at 3 deg/sec, a 180-degree turn will take 60 seconds. If the entire turn is performed at 63 knots, the aircraft will travel 1.05 nautical on a half circle (assuming zero wind). The radius of the circle will be the circumference, 2.10 divided by 2*pi = 0.3342 nm. Therefore, x = 2*0.3342 = 0.6684 nm.
If starting at 90 knots and slowing down to 63 knots, the trajectory will not be a a semi-circle but rather a section of a spiral. The starting radius will be 0.4775 and the final radius 0.3342. In this case, x will be approximately 0.8117 nautical miles. To get an exact value for x, an integration must be performed.

I'd like to second your point on having the approach speed being achieved at the abeam (position A on the diagram). You may, at your option, want to add that the military constant turn approach is a constant airspeed approach with the approach speed being stable at the abeam position ... in part for the reason that you cite (why make it more complicated than it needs to be ....)

This sounds like a power-off 180. Your numbers may be off based on the fact that you are going into your descent with absolutely no power available. You would be better off squaring off your approach with a downwind to base to final configuration with 90 degree turns. If you feel like you have too much lateral distance from the runway for all three legs done properly, you may try a downwind to diagonal base to diagonal final. This can be accomplished either with a shallow turn, then a steep turn, then a shallow turn. Or, the better option of side-slip, steep turns, side-slip.


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Aeroplane protection against lightning strikes
I would like to know what kind of protection are available on planes against lightning strikes.

Does this question help?


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For a 180 degree turn after takeoff, what is the normal turn radius for the A320 and 737?
I'm looking for some rule-of-thumb guidance on this matter. It relates to route 4, the westerly take off from London Gatwick (LGW).

Related: What does it take to turn a 747 around 180 degrees?. If you are looking for the simple figure, then it seems to be 8.28 nautical miles at cruise speed, taking off will be smaller.

Not sure it's a duplicate. The 747 question is about a 180 at cruise and the heavy a/c question is about limited turn rates. This question is asking for the turn radius with a normal bank limit (15 deg?) at Green Dot airspeed.

While in theory possibly a duplicate of the other question, and while the physics are very well explained there, the numbers to be used for takeoff and landing aren’t given in the other thread.
The following works as a rule of thumb for most commercial airliners: Maximum bank angle after takeoff with all engines would be around 25 degrees, with a failed engine it would be around 15 degrees until minimum clean speed is reached and the flaps are up and 25 degrees after that.
True air speed shortly after takeoff shouldn’t be much above 200 knots for most weights, airfield elevations and temperatures encountered except in extreme circumstances.
Plugging both these into the formula for turn radius explained elsewhere gives just above 2300m radius on all engines, and just above 4000m radius with a failed engine and before cleanup.
Brief answer, but I hope it helps!

You could look to the Standard Instrument Departure (SID) routes published by NATS for a guide as to what is done - as opposed to what could be achieved.
http://www.nats-uk.ead-it.com/public/index.php%3Foption=com_content&task=blogcategory&id=94&Itemid=143.html

Welcome to Aviation.SE! This answer could be improved by providing radii from those procedures.

This doesn’t change the answer but touches upon a wide issue in the industry for some background information: SIDs (in fact, all procedures, but SIDs are most critical) are designed to standards which work most of the time, but which still are not aligned with aircraft performance at all. There are many procedures where airlines need to take precautions (most often: restrict takeoff weight) in order to meet e.g. turn radius or climb rate requirements. Checking departure plates for turn radii is therefore relevant and interesting, but not necessarily indicative of what aircraft will achieve.


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How will a prolonged series of steep turns produce a stall in subsequent level flight?
In Stick and Rudder, the author warns pilots against the unreliability of judging airspeed and hence “buoyancy” — his term for how far the airplane is from aerodynamic stall — by throttle position, engine noise, and nose attitude.

Perhaps the most deceptive of these factors is g load. When an airplane, flying at a certain speed, goes into a turn and loads itself down with g load it assumes larger Angle of Attack and this gets closer to the stall. That has been described earlier in this book. But it isn’t the whole story. At the larger Angle of Attack, the wings have more drag, and thus the airplane will slow up, unless the throttle is opened wider. The airplane assumes a still higher Angle of Attack and gets still closer to the stall! Few pilots realize how strong and dangerous this effect is.

Langewiesche, Wolfgang. “The Flying Instinct.” In Stick and Rudder: An Explanation of the Art of Flying, 58. New York: McGraw-Hill, Inc., 1944.
He then gives a surprising example.

The average small airplane, fully loaded and with its throttle set at cruising, is actually unable to hold indefinitely any turn banked much more than 45 degrees! The effect just described will slow it down gradually, as it circles, so that the pilot’s stick comes farther and farther back; until finally, after perhaps twenty turns have been completed, it will stall: stall, mark you, out of level flight with cruising throttle!

ibid.
Why doesn’t nosing over to leave the steep turns for straight-and-level attitude with open throttle produce sufficient airspeed to avoid the stall?

I think what is described is entering the regime of speed instability on the backside of the power curve. Additionally, the described scenario assumes the pilot holds altitude by pulling back no matter what. Trading altitude for sufficient airspeed in descent will restore normal flight at previously trimmed cruise conditions eventually.

I think the author's comments assume that the pilot has not taken action to maintain airspeed with the increased drag, by either increasing the throttle, (or, if the aircraft does not have sufficient excess power to hold airspeed at the higher bank angle, initiated a descent).  [Obviously], if you don't maintain sufficient airspeed, eventually the aircraft will slow down and stall.

"When an airplane, flying at a certain speed, goes into a turn and loads itself down with g load it assumes larger Angle of Attack and this gets closer to the stall. " -- I don't believe this is true.

A prolonged series of steep turns will not produce a stall in subsequent straight and level flight.

"after perhaps twenty turns have been completed, it will stall: stall, mark you, out of level flight with cruising throttle!"

In this case "level flight" means not climbing or descending while still in a steep turn.
Stopping the turn by rolling level would unload the wings and prevent the stall. Nosing down would also unload the wings and increase airspeed, also preventing a stall.

Throttling up from cruise power to climb or TOGA power would also increase airspeed and prevent a stall.

Well, lowering the pitch attitude to reduce the AoA during the turn will nullify the onset of the stall at the expense of loss of altitude.  Langeweisch’s point is that for a smaller aircraft ie an airplane with little reserve power available to climb and with the throttle setting for cruise power and not increased during the turn, holding a continuous steep turn at a constant altitude results in so much additional induced drag that the airplane will begin to decelerate.  Doing so requires additional pitch up to hold altitude which again increases drag, creating a vicious circle.  Sooner or later the airplane will be so slow that the pilot will exceed the critical AoA using elevator pressure and stall the airplane.  This will occur at a speed much higher than it would in straight and level flight.  The point here is that power settings have to be adjusted in order to maintain constant altitude and airspeed in a steep turn, as would be expected.

The simplest explanation is that when Langewiesche says "it will stall... out of level flight with cruising throttle", he is describing a situation where the aircraft is still banked, with insufficient power to maintain a constant airspeed, and the pilot is continually moving the stick or yoke further and further aft to maintain altitude, bringing the aircraft deeper and deeper into the "back side of the power curve".
Now let's consider some other possibilities.
While there's a lot of good information in "Stick and Rudder", there are also some flaws within.
For example, Langewiesche claims that in turning flight, sometimes it is better to center the slip-slid ball with an elevator input rather than a rudder input.  I've never found this to be possible.
In general for a given position of the control stick or yoke, or for a given force exerted by the pilot on the control stick or yoke, an aircraft flies at a lower angle-of-attack in a steep turn than in wings-level flight.  This is a consequence of the fact that a turn involves a pitch rotation rate, which creates an aerodynamic damping effect, which creates a pitch torque on the tail that decreases the wing's angle-of-attack.
If you set the throttle and elevator trim to maintain altitude and airspeed in a medium-banked or steep-banked turn, and you then you roll to wings-level without changing the throttle position and without pushing forward on the yoke, not only will the flight path curve upward, but the angle-of-attack will increase, and the aircraft very well may stall.
However, starting from a constant-altitude constant-airspeed steep turn, if you push the stick or yoke forward to avoid climbing as you roll to wings-level, and the aircraft had not yet reached the stall angle-of-attack in the turn, then the aircraft is not going to be at risk of stalling once it enters wings-level constant-altitude flight at the same throttle setting, even if there was a substantial loss of airspeed in the turn.
Things are a bit different if the airplane is allowed to descend at a very steep dive angle in the turn.  A steep descent path does "unload" the wing to some degree, as drag rather than lift supports part of the aircraft weight.  Still, it is hard to imagine that this effect would be strong enough to cause the aircraft to stall once the pilot reduces the bank angle to zero and attempts to maintain a constant altitude, as long as the pull-out from the descent is not too abrupt.
Note the reference to "cruise power" in Langewiesche's warning.  Presumably this means that the throttle or power lever is fixed in a position appropriate for crusing flight.  Langewiesche's warning appears to be aimed at a situation where the aircraft is rapidly losing airspeed in a steep turn and ends up deep on the "back side of the power curve", with the airspeed continuing to decay, as the pilot trades airspeed for altitude.  Still, if we are talking about a substantial bank angle and the airspeed has not yet dropped to the (accelerated) stall speed, it is hard to imagine that once the airplane is rolled back to wings-level flight and the angle-of-attack is reduced, it will still be so deep in the "back side of the power curve" that it will not be able to accelerate while maintaining altitude, even with no increase in power setting.  Perhaps in a really extreme case where aircraft was just about to stall before the pilot started to decrease the bank angle, the pilot might have to let the aircraft descend a bit first rather than trying to maintain altitude immediately upon reaching a wings-level attitude, to allow the airspeed to start to increase, especially in a jet where the "backside of the power curve" may extend further above stall speed than in an aircraft with a propeller, given that the thrust lever is assumed to be fixed at a cruise position.

In a turning descent, yes the wings are unloaded, but the risk remains rolling out as the plane has a vertical component.  Some commonality here to recovery from a side slip: relax elevator and roll to level coordinated with rudder.

edit needed "extreme case where the aircraft was just about to stall"


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After a crash, does the information stored on flight recorders have expiration dates?
After the recent announcement of the recovery of the flight recorders of AirAsia flight were recovered, I was wondering if black boxes deteriorate after a set amount of time.
As of now, nothing of the plane MH370 has been recovered, including either of the flight recorders. In another downed flight in the past, it took over two years for the for the black boxes to be recovered from the ocean, and even then the information in the black boxes were intact.
So do these black boxes ever expire? Or do they always keep the information intact throughout the years?

NAND flash can't last forever and will eventually deteriorate, but I don't know if that's a matter of months or millennia. Certainly being at the bottom of an ocean will shield it from most radiation.

@raptortech97 iirc, in 2015 there was a study that showed that unpowered flash memory reliably stored data for one to two years, depending on ambient temperature.

@DanilaSmirnov: I've got a few flash drives that sat around inert for considerably longer than that and later were powered up without any problems, and that's just consumer-grade flash; I'd expect that the top-of-the-line flash used for things like flight recorders would be yet more resilient still.

Everything will expire one day, including our Sun. Flight recorders are no exception.
Older flight recorders used magnetic tapes. They used to work like any other tape recorder. At present, solid-state memory boards are used. These are considered much more reliable than magnetic tapes, because no moving parts are involved like magnetic tapes.
Data from both recorders is stored on stacked memory boards inside the crash-survivable memory unit (CSMU). A CSMU is:

... is collectively the solid-state memory chips and a hardened metal
  container filled with specially designed heat insulating material. It
  is this container that provides the survivability, for it is able to
  withstand massive crushing loads, intense heat, and exceptionally high
  G forces, all of which is proven by crash survivability testing.

Image Source
You can see that the memory boards are inside stainless steel shell, which is designed to withstand the crash. Although there is a limit of writes on solid state memory, after a crash there are no more writes.
When the FDRs/CVRs are recovered from a crash scene, there are various methods to retrieve data, depending on the condition of flight recorders. This process can take weeks or months to complete.

Further reading: How Black Boxes Work

Every aviation accident is different. The aircraft flight data recorder is designed to survive likely scenarios, but successful recovery of the data stored on it is not guaranteed. Wikipedia has a List of unrecovered flight recorders which is related.
There is no predetermined amount of time that a flight data recorder might "keep" its information intact. The data is stored on solid state devices these days, so presumably the information would be recoverable as long as the enclosure remains watertight and the internal temperature does not exceed the physical limits of the components. Neither of those conditions are assured and the information may be lost at any time.

The one thing that does certainly deteriorate is the battery powering the locator stuff, meaning after a month or so it becomes much harder to find.

Modern solid state storage isn't going to be bothered by water either. You may need to rebuild the interface, though. Even consumer grade SSD's will probably survive submersion, if powered off in time and cleaned before restarting. And you can realistically expect 20+ years of data retention.

@MSalters: Even seawater?

@GregHewgill: Seawater may or may not be kind to exposed metallic contact pads on the chip, but they can be recreated if you're determined, and the actual silicon that contains the data is pretty resilient. There are metal traces inside the chip that are necessary for its function, but they wouldn't be exposed such that the water can get to them in the first place.

I expect the chips themselves to be encased in epoxy. This helps them survive crashes; it would be unfortunate if the chips came loose. Even without that, the actual silicon is almost always embedded in some kind of shell, often ceramic.


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When were checkerboard fiducial markers first used in aircraft development?
It's common to put checkerboard fiducial markers on aircraft to help analyze rates and orientations from photographs and film.

When was this practice first used on aircraft?
Flight test versions of the German V-2 rocket were painted in a checkerboard scheme, presumably for fiducial-marking purposes (or just high visibility); was this already established practice at the time of the first V-2 test flights in 1942?

I had never noticed that on a large plane before, only on rockets. Thanks for pointing that out.

This was not already established practice in 1942.  Not even in the early 1950's NACA crash tests, which were so methodical that you'd have expected these checkerboards:  seven movie cameras along the runway, a flashing light atop the fuselage for movie synchronization, a pile of onboard cameras and instruments, white paint and red-dyed fuel for better imaging.  The closest this came to checkerboards was dotted lines on the fuselage sides.
This long NASA video includes many images of these aircraft.  No checkerboards anywhere.
A skim through online photos suggests that even automotive crash tests didn't start using checkerboard fiducials until the 1960's.

I think the dotted line markings are intended to serve a similar purpose, but this is good info.


text:
Does a left spin differ from a right spin for a single-engine propeller aircraft, in terms of spin characteristics & ease of recovery?
Given a single-engine propeller aircraft with its nose-mounted propeller rotating on the right-hand side when viewed from the cockpit, and given the typical effects like P-factor, prop-wash and gyroscopic forces associated with the propeller -

Would there be any differences between left-hand and right-hand spin modes? (Differences both from the physics perspective as well as perceptional difference from the pilot's point of view. For example, the differences could be there from a theoretical perspective but minor enough that the pilots can ignore them in real life).
If the answer is yes for Q1, which side, in this particular case, would have a more severe spin in terms of spin rate, loss of altitude and so on?
If the answer is yes for Q1, which side, in this particular case, would have a harder recovery compared to the other side?

To reduce variables, let's assume there are no asymmetries in the aerodynamic configuration which may make the aircraft favor one direction over the other for  spin and we are only considering the effect of propeller-rotation-direction-related effects on the spin.

Possible duplicate of Why the need to use right rudder during stall recovery?

You may edit the title to (i) be more specific (ii) transfomr it in a question (this is a Q&A website). I suggest "how are handled differences between left and right spin for a single engine propeller aircraft?"

Chipmunk, left-handed engine: Spinning to the left, recovery takes 3/4 turn, spinning to the right, recovery takes 1/4 turn. In either case, descent rate is 6000ft/min, so not affected by the airflow direction.

It differs but not as much as it does for jet aircraft.
This may seem counter-intuitive, but in spin, inertia and gyroscopic effects play major role.
On propeller aircraft, the most practical difference must be with inadvertent entering spin, where power (and the associated asymmetry) is significant. But after entering spin, the first thing one does is reducing power to idle. This makes aerodynamic asymmetry ('P-factor' etc.) negligible (unless the tail is deliberately offset, as is done on many single-prop aircraft), and the prop gyroscopic effect is rather small.
Jets, while looking perfectly symmetric, still have engine(s) rotating one way (with a few notable exceptions), and their gyroscopic moment is very significant, even at idle. (The rotor is much heavier and spins much faster). Most jet fighters have very asymmetric spin characteristics, to the point that one spin may be stable and difficult to recover while the opposite spin be unstable and difficult to enter.
If the gyroscopic moment tries to raise the nose in a given spin rotation, the spin will usually be unstable. For example, MiG-15/17, with its left-rotating engine, had a very unstable right spin, which tended to change to left over time.

A well known spin recovery technique is PARE.  Power to idle, Ailerons neutral, Rudder Away from spin, Elevator nose down.
Power to idle is critical to avoid complications in spin recovery.  Now, aerodynamicly, spin behavior recovery is much more similar left or right, with the right being slightly easier to recover from.
If your plane is stable, and CG is set right, it should not spin unless it is forced to.  Rudder control remains effective through stall, and is your best friend to avoid, or stop, a spin before it becomes fully established or flat.

"Now, aerodynamicly, spin behavior recovery is much more similar left or right, with the right being slightly easier to recover from" Why? Does this change depending on the rotation of the prop? This is the crux of what the OP is asking, not recovery techniques or weight and balance.

Gyroscopic effects, even with an idling engine make upright left spins flatter assuming a right turning propeller.
The left yaw force applied to the propeller moves 90 degrees in the direction of rotation and the prop disc is forced to tilt upwards. That force is transmitted through the engine to the airframe.
How much flatter will depend on the mass of the propeller, it’s speed of rotation and all the other things that vary from type to type.
Because the spin is flatter, the rotation is slower in that direction, due to conservation of angular momentum, not unlike a figure skater extending her arms while spinning.
It is certainly noticeable in the Pitts Special. Not only is the upright left spin flatter at idle power, adding power while spinning raises the nose.
To perform upright flat spins with a right turning propeller you need to use left rudder.

In the Pitts upright spins to the left or right with the engine at idle power recover about the same. Any difference is more likely airframe rigging than gyro. However if the left upright spin is made more flat with power it will take longer to recover.

Two things have to happen simultaneously to cause a spin: stall and large enough yaw rate. To recover from a spin you need to stop both of those. Therefore anything that increases the intensity of either a stall or yaw rate will hinder you recovery.
Specifically talking about the propeller contribution: let’s say we have a clockwise prop, which produces left turning/yawing tendencies. Since it creates left yawing motion; left turning spins will be easier to enter and harder to recover from than the right spins. Because there will be more yawing moment that we need to overcome.
However whether the difference would be perceivable or not by the pilot would really be depended on the aircraft, power setting, idle power/torque, size of the prop, aircraft’s inertial characteristics etc.


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Why is one of two parallel runways sometimes closed in foggy weather?
A few times, when flying into SFO, me and my fellow passengers were informed that due to foggy weather one of two parallel runways there is closed, causing delays. So, a few questions:

Why can only one runway be used during fog? During an instrument landing, if the instruments are precise enough to land the plane exactly in the middle of one runway, then surely they are precise enough to differentiate between two runways?
Is this standard practice in all airports or something specific to SFO? Is there some minimum distance between parallel runways above which it is safe to keep them both open in foggy weather?

This might not answer your question, but you may find http://www.skybrary.aero/index.php/Parallel_Runway_Operation interesting.

While ILS is precise enough to guide the aircraft precisely onto the runway, it is only so precise in the immediate vicinity of the runway.
The instrument measures angular divergence from the runway axis. So while the one dot offset is just a few metres over threshold, it is much more at the point where the aircraft normally intercept the localizer, which is usually at least 10 miles out for large aircraft. At KSFO the runways are so close to each other that while the localizer could perhaps ensure separation in the final phase of landing, it can't ensure it in the earlier part.

SFO makes use of simultaneous close parallel approach operations.  This allows higher density operations than would otherwise be possible for runways spaced so close, but to make use of these ops, in SFOs case, requires 1600 ft ceilings and 4 sm visibility due to the requirement that aircraft maintain visual contact during close parallel operations.
It does look like SFO can run the ILS approaches simultaneously outside of close parallel operations, but is possible the required spacing makes its pointless to use both runways.  If weather was bad enough that cat II ops were in effect, I don't see any verbiage on the cat II charts indicating simultaneous ops are approved.
Regardless of how precise your instruments are, there are strict requirements on how close you can be to another airplane in the approach phase and that separation be maintained if both parallel aircraft perform the missed approach.
The ability to run parallel approaches in low visibility depends on how far apart the runways are laterally.  Airports like IAH and ATL can run triple parallel ops and if you take a look at their runway layout you will find they are spaced quite far apart and may be displaced relative to one another.

Yes, ATL can perform triple parallel approaches while also performing two additional parallel departures. It has five parallel runways. DFW also has 5 parallels.

@reirab: ORD is another airport with five parallel runways (with a sixth parallel on short final, expected arrival 2020).

@Sean Yeah, it does now. The present 10R/28L was still under construction back in 2015 when I wrote that comment, though. I believe ATL now also has a 6th parallel in the plans, though it's not under construction yet, as far as I know.

I didn't see specific distances mentioned for the second part of the question.
If the runways (centerline to centerline) are separated by at least 4300 feet (and other conditions are met), the airport can conduct simultaneous instrument approaches.
If the runways are ate least 2500 feet apart, they can conduct staggered approaches (both runways in use, but aircraft do not approach alongside each other).
As a reference, the SFO runways have a centerline separation of 750 feet.

From the AIM
http://tfmlearning.faa.gov/Publications/atpubs/AIM/Chap5/aim0504.html#?F8258ROBE

It also shows the situation that waivers are possible for separations less than 4300 feet if additional conditions are met.

This should be marked as the correct answer

The finals controllers use FAA order 7110.308 which is simultaneous ILS approaches to closely spaced parallels. It’s waives all of that. Usually a slightly staggered operation, SFO has a waiver to go down to 1.0 mile offset between aircraft in the same “pair”.

It's not.  Precise enough, that is.
There's a point in the ILS landing process called "Minimums".  At that point the pilots must see the runway or throttle up and go-around.  Assuming they have seen the runway, they must be prepared to stick-fly it onto the centerline, and then keep it on the centerline during braking, against crosswinds (still pushing on the tail), asymmetry in braking or reverse thrust, etc.
The precision of this varies by different classifications of wayside and on-airplane equipment, so both minimums and the "when you take over and stick fly" points also vary (separately). You can't decree that every landing airplane has the latest & greatest.
In fair weather, SFO ops (when my cubicle was directly under the flight path) involved bringing in airplanes near abreast, virtually wingtip to wingtip. That's not the computer either. That is the slightly trailing plane stick-flying it, using the Mark 1 eyeball for separation.  And that depends on both fair weather and a high cloud ceiling, so they can visually line up (with each other) early in the approach.
The abreast (not staggered) approach was required for capacity reasons, not for landing but for takeoff: these two aircraft needed to land simultaneously and clear the runway intersections simultaneously.  There were two departing aircraft lined up on the two cross runways to start their takeoff roll the moment this pair swished by.
I've even seen a triple: a Japan Air Lines 747 and two F-16s. Guess which day it was.

They don’t close a runway for fog or bad weather. That would never happen. They close runways for scheduled maintenance or if something happened like a bird strike and the port authority needs to get out there and clean it up. SFO can run dual ILS operations to 28L/R in very low visibility with a 1.0 mile stagger between aircraft. The arrival rate for that operation (FAA order 7110.308) and full blown sidebys in visual conditions is only a difference of 10-12 aircraft per hour.  Which is enough to cause some delays. When the weather gets really bad pilots will start requesting category 3 ILS approaches due to company requirements(?) Our only cat 3 ILS is 28R which is also the longer runway. So more aircraft will request it. The left is still open, just not used as much.


text:
Does stall angle of attack in inverted flight change due to the camber of an asymmetric airfoil?
What is the stall angle in an inverted flight configuration? How does it relate to the stall angle in normal flight?

As visible in the image below, in upright flight the lower pressure is on the extrados of the wing. In inverted flight the lower pressure is on the intrados.

(source)
The air stream separation at the stall will occur on a side with different characteristics. One could expect the stall will happen differently.

Equivalent representation, where the gravity is inverted and the wing orientation remains in the same direction. Flying inverted implies flying at a negative angle of attack.

The values taken into account are the airflow direction and the chord line, reflected in the angle of attack value.

As commented, while the two previous images suggest a wing in horizontal flight, the situation can be extrapolated to any stable linear trajectory with a negative AoA.

The horizontal plan or the pitch angle are not necessary to determine the stall angle (though they influence the stall speed).

Think of it this way.  The wing doesn't know it's upside down.  All it knows it that the airflow is of a certain speed, from a certain angle.  The diagrams you've shown are for different pitch angles.

@Federico No it's not. Please show me in the lift equations where wing orientation is taken into account.  The wing behaves identically for a given speed and a given AoA.

@Federico Nope, you are confusing pitch with AoA.  Aircraft flying straight and level.  AoA x degrees.  It will generate a force upwards of y newtons. Now turn it upside down and keep the AoA the same.  It will now generate a force of y newtons downwards.  The force does not change.  In order to maintain straight and level, you will need to adjust pitch, such that the A0A is adjusted and lift again = gravity.

@Federico In the second picture, the pitch is different, and therefore the  AoA.  It is not a point for debate that for a given AoA and speed, the wing behaves in exactly the same way.  I don't get why you are arguing that this is not true.  The wing does not know it's upside down.

Related: http://aviation.stackexchange.com/questions/19242/is-the-stall-speed-different-at-1g

Short answer: Asymmetric airfoils have different positive and negative stall angles, the largest absolute value of the two depends on factors like nose shape and camber. With positive camber (normal and utility aircraft), the negative stall angle can be the largest (in absolute values) but the maximum negative lift available before stall will be smaller than for the positive stall. Larger Reynolds numbers push the stall further away in both directions
It depends on the airfoil. With symmetric airfoils, the stall angle is the same for positive and negative stalls. Positively cambered airfoils (the sort mostly used) have their negative stall at a smaller absolute value of the lift coefficient compared to their positive stall, but the stall angle can well be at a higher absolute value.
Below you see a polar plot for a supercritical airfoil which I used for this answer. The positive stall angle of attack is 8°, while the negative one is around -10°.

Polar plot of the R2A airfoil at Mach 0.6 (own work)
The stall angle depends on details of the nose contour and the camber: Positive camber means that the zero lift angle is shifted to negative values, so there is some bias to negative values in the polar. However, if the lower part of the nose has very high curvature, it will create a high suction peak which leads to flow separation just aft of the nose already at a small negative angle of attack.
One extreme case would be the Göttingen 417a airfoil. Airfoiltools unfortunately plots only a range of Reynolds numbers suitable for model airplane enthusiasts, but the plot below should get the point across. The positive stall angle is 12° at the highest Reynolds number, while the negative stall angle is only around -8°.

Gö 417 lift over angle of attack. The lowest Reynolds number (blue line) is 50,000 and the highest is 1,000,000 (olive green line). Note that all curves are XFOIL predictions - real-world data might look differently.

Since an AOA of 180 degrees is hitting the trailing edge, is 90 degrees from straight above and 270 degrees from straight below, or are they both 90 degrees?

@Lnafziger: Yes, but 90° is from straight below and 270° is from straight above. The airfoil makes a full rotation around the Y-axis (spanwise axis) for one 360° rotation in its angle of attack (or you rotate the flow direction and keep the airfoil fixed, as you like).

Okay, so what I was trying to say before is that the AOA is not the same for an upright versus an inverted airfoil (in un-disturbed air) because there is a 180'degree difference.  For the same AOA, it makes no difference whether the airfoil is upright or inverted,

@Lnafziger: The simple formula AoA = pitch angle - flight path angle doesn't work in inverted flight. The coordinate system for pitch will not rotate, that for the airfoil's AoA will, however, so the pitch angle is nearly the same small positive value but the AoA is a small negative value in straight inverted flight. Increase pitch, and the AoA will become more negative (there is an additional cosine involved which is 1 in upright and -1 in inverted flight).

So the R2A airfoil is harder to stall in inverted flight?

@Sean: No, the angle of attack is not relevant. Look at the lift coefficient instead: While upright the max. c$_L$ is 1.3, inverted it is only -0.75. So the inverted stall speed is 31% higher than the upright stall speed. Post-stall behavior is roughly similar, but this being an ISES calculation, the real behavior might be different.

You are basically comparing a situation with positive $\alpha$ (above) with a situation with negative $\alpha$ (below).
You could obtain the same situation by pitching down: see how in the second picture your flow direction arrives from above the chord line (in the reference frame of the wing).
If your airfoil would have been symmetrical, the critical positive and negative $\alpha$ would have the same absolute value, only opposite sign, but you show a cambered airfoil.
I currently do not have my aerodynamics book at hand, but google helps us:

As you can see in the image, adding camber to an airfoil shifts its $C_{L\alpha}$ line towards negative values.
This is desirable because in this way you can have lift even when the angle of attack is 0 (and with no or little drag increase). Another consequence it that the maximum positive $\alpha$ will be smaller than the uncambered case and the negative one will be even more negative (but with some limitations, the Runge-Kutta condition at the trailing edge will affect the shape of the negative $C_{L\alpha}$ curve)

I understand the role played by the camber to maintain the AOA near 0 (and minimal drag) in cruise. What I don't understand is whether this camber will affect the stall angle in inverted flight.

@mins inverted flight or negative AoA is the same thing.

The way to prove it would be to continue to plot through to -25 degrees AOA.  The symmetrical plot would be a mirror image.  The cambered would not.  BTW, cambering the wing, as airliners do, vastly increases lift generated, giving airliners a speed envelope few aircraft enjoy.  Figure 43.6 may be an oversimplification for comparative purposes.

Notice inverted flight is very rare in birds, which have heavily cambered wings similar to the GO 417.
It is important to remember that inverting an asymmetric wing, in simple terms, is reversing all that is good about the lift generation "right side up".  The result is a loss of lift at that speed and angle of attack.  Further more, there is a very good chance the stall angle of attack of the inverted wing is lower.
In the case of a heavily undercambered wing, inversion would likely be a disaster.  Wind tunnel/smoke would show heavy turbulence over the top and very little lift from pressure underneath the wing.  Notice the two great virtues of thin undercambered wings have been reversed.
On the other extreme, fully symmetrical wings show little difference when inverted and are popular in aerobatic aircraft.
The flat bottom will behave better than the undercambered, but when inverted will generate less lift at a given AOA and exhibit flat plate stalling characteristics (stalling at a lower AOA).
Amazing how much interest the movie is generating.  We'll have to give Denzel a symmetric wing, and Sully a good set of floats.

"Further more, there is a very good chance the stall angle of attack of the inverted wing is lower.": The question is about the change in the stall AoA, and you don't seem to know the answer.

Well, what do you think?  For the flat bottom (see picture) inverted, the stall angle will probably be less.  Give me a wind tunnel, I'll give you proof.

The point is I don't see what does your imprecise post add to the very well documented selected answer from a knowledgeable expert.

Haven't heard your "knowledgeable" answer yet.  2.  If you think my answer is incorrect, please say why.  3. My answer is based on NACA short films.  4.  Please don't waste comment space on personal opinions.  5.  If you think wings should be flat on top and rounded on the bottom, we have wind tunnels for that.  6. As a retired researcher, my standard of "knowing" is validation by testing.  As I have not tested that particular wing, I say "seems likely".  If you disagree, fine.  I will be happy to consider your point of view

"Haven't heard your "knowledgeable" answer yet": Not mine, this one. Documented with the checked values -10° vs +8° in contradiction with your assumption "the stall angle of attack of the inverted wing is lower". You could now tell me -10° is lower than +8, indeed.

We'll, now we are getting somewhere.  I have stories on learning how to pour beer, but I will skip them for now.  Thanks for your observation.  Now, with cambered wings, 0 lift is going to be at negative AoA, there for the RANGE of AoA available to generate lift upright and inverted would start from that point.  For example 0 lift AOA is -4 degrees.  For sustained inverted flight, one would have only 6 degrees to work with before stall.  Upright, one would have 12 degrees to work with, plus much better lift performance.  This would support "stall angle of attack is lower inverted".  Thanks!


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Why might this trans-pacific flight not follow a more direct route?
I notice that this flight from DFW to PVG has a path that’s not a single arc of a great circle. Rather, it looks like it flies to some city in California and then takes a direct route for the remainder.
Why might it do that, instead of following a more direct route, such as a great circle route?  It didn’t stop along the way, so why would it need to overfly an intermediate location that’s not on the direct route?
(flightaware.com) American Airlines 127 Thursday 04-May-2017
Compared to great circle route:
(gcmap.com)

P.S. the FlightAware page claims “unable to decode route”

Very rarely does a flight follow the great circle route all the way. Every day the route is changed due to winds - you want to find the tailwinds and avoid the headwinds. Other considerations include airspace restrictions (China is notoriously bad for that), ETOPS, or weather.

Possible duplicate of Why do pilots use airways instead of just "flying direct" every time?

It looks to me like your Great Circle route would take them over North Korea.   I don't see any problem with that, do you?

That dogleg over Japan looks like what KAL 007 was supposed to have done.  But I assume that Russia is less sensitive about overflights than the Soviet Union was.  (At least for now.)

@mins I'm guessing the chance of American Airlines flying something that isn't ETOPS certified on a 14+ hour flight across the Pacific is roughly nil. Also, the great circle path itself is actually pretty well covered for ETOPS purposes in this case, thanks to how close Alaska and Russia come to each other.

Looks like they were avoiding a storm system from Oregon north into Canada.

Makes sense - Blame Canada! was my first thought, too.

I think the deviation near Japan may have been to avoid storms over the Sea of Okhotsk.  Take a look at the images here from 5/4/17;  the times listed are BST, so the plane would have been in the area around 06:00 that day (give or take an hour.)

@MichaelSeifert Probably a combination. I don't think American would overfly North Korea regardless of the weather unless the options were basically down to overfly DPRK or crash. It you look back through the history on that flight, you'll see that it always either makes that dogleg over Japan or else flies over Mongolia, remaining well clear of DPRK on the other side.

@MichaelSeifert Plus, the US Navy is currently running exercises in the Sea of Japan - basically poking the badger. Not a good time to overfly the area